#include "g_local.h"
#include "fileio.h"
#include "cycle.h"

char *cycle_get_next_map(char *currentmap){
	char	*linebegin, *lineend;
	map_t	*newmapt;
	map_t	*walk;
	map_t	*maphead = NULL;
	map_t	*maptail = NULL;
	
	// load up the map list
	linebegin = ReadTextFile("maps.lst");
	if(!linebegin)
		return (NULL);						// couldn't load file
		
	while(1){
		// find end of line and terminate string there
		lineend = strchr(linebegin, '\n');
		if(lineend)
			*lineend = '\0';
		if(linebegin[0] == '\0')			// stop on blank line
			break;
			
		// make new linked list entry
		// (mem is freed on level change automatically)
		newmapt = gi.TagMalloc(sizeof(map_t), TAG_LEVEL);
		newmapt->next = NULL;
		newmapt->mapname = linebegin;
		
		// link it into the list
		if(!maphead){
			maphead = newmapt;
		} else {
			maptail->next = newmapt;
		}
		maptail = newmapt;
		
		// if we truncated the string, then the start of the
		// next line is one beyond that.  otherwise, we
		// just processed the last line, so we are done
		if(lineend)
			linebegin = lineend + 1;
		else
			break;						// stop if last line
	}
	
	// look for entry of current level
	for(walk = maphead; walk; walk = walk->next){
		if(Q_stricmp(walk->mapname, currentmap) == 0)
			break;
	}
	
	// if we found an entry and it is not the last one
	// then return the name of the next level
	if(walk && walk->next)
		return (walk->next->mapname);
		
	// either we were on a level not in the list or the
	// last level in the list.  either way, just start at
	// the beginning of the list
	if(maphead)
		return(maphead->mapname);
		
	return(NULL);		// couldn't load file?
}